A plastic lens formed of an optical resin excellent in transparency has been used in a wide range of fields due to the light weight and the excellent processability thereof instead of an inorganic glass lens, and is particularly useful as a spectacle lens.
A spectacle lens is demanded to have an ultraviolet ray absorbing power for protecting eyes from a harmful ultraviolet ray, and an ultraviolet ray absorbent may be added in production of a spectacle lens formed of a plastic material in some cases. However, the addition of an ultraviolet ray absorbent has caused a problem of yellowing of the plastic lens itself. The yellowing of a plastic lens may also occur in the production process thereof including a heat treatment, and various investigations have been made for preventing the yellowing of a plastic lens from occurring.
For example, it has been known that a bluing agent or a blue dye is added in the production process, but a bluing agent and a blue dye may not provide sufficient effect in some cases due to the poor solubility thereof in some kinds of monomers and the discoloration thereof during the polymerization.
PTL 1 describes a method for producing a lens including the addition of an anthraquinone compound having a particular structure as a blue dye to a urethane resin, but the production method is limited to a urethane resin, and the transparency of the resulting lens is not satisfactory in some purposes.